Due to the development of electronic communication industries, portable terminals such as mobile communication terminals (i.e., cellular phones), electronic pocketbooks, Personal Digital Assistants (PDAs) and the like have become widely used in modern society while becoming a significant means for delivery of information changing quickly.
Generally, the portable terminal has a keypad that provides a means of inputting information. Additionally, portable terminals have been miniaturized to the point that they may be difficult to be configured with these keypads. Although keypads may be provided in the relatively restricted space provided by the miniaturized portable terminals, and unintentional consequence is produced in which incorrect input occurs because a key size of the keypad is small or a key interval of the keypad is dense. After all, a user is often generally cognizant of the necessity of being cautious to not input incorrect information through the keypad. This causes a burden on the user. Generally, to solve this problem, a technique for presenting words similar with an incorrect input word has been proposed. This existing technique includes comparing an input character string with a previously registered correct character string. This technique, however, has a disadvantage that it is dependent on a particular form of character. Further, because incorrect input circumstances may be different according to the type of keypad, the manner for presenting a similar word may be difficult to accomplish when multiple similarly spelled words are used. For one example, a combination keypad is of a scheme in which two or more letters are allocated to one key and, whenever a key is pressed, a letter is changed and input. Compared to the known Qwerty keypad, the combination keypad has fewer keys in number so that the combination keypad may suffer incorrect input more frequently following the number of times of key pressing than incorrect input of an adjacent key.